BAY RIDGE — A four-alarm fire ripped through the 81st Street home of Bob Howe, president of the Merchants of Third Avenue business organization, early this morning, destroying the dwelling in which he and his family lived for 28 years, Fire Department officials said.

Howe and his wife Diana ran out of the house after their next-door neighbor banged on their front door to warn them about the fire.

“Thank God for my neighbor. Thank God we got out in time,” Howe said as he stood on the sidewalk in front of his burned-out home at 168 81st St. a few hours after the fire took place. “We got out just in time. We weren’t out of there five minutes when the whole house went up in flames.”

All of Howe’s belongings were destroyed in the blaze.

“We’re devastated,” he said.

The fire consumed the first and second floors of the three-story wood-frame house, according to a Fire Department spokesman.

The first 911 call on the fire came in at 3:27 a.m., the spokesman said. The blaze quickly escalated into a four-alarm fire.

“Over 40 units were called to the scene. We had more than 170 firefighters there,” the spokesman said.

Four firefighters suffered minor injuries, according to the spokesman, who said the injuries included heat exhaustion and smoke inhalation. The firefighters were taken to Lutheran Medical Center for treatment.

There were no other injuries, the spokesman said.

It took over an hour for the firefighters to bring the blaze under control.

The cause of the fire is unknown, according to the Fire Department spokesman.

“It’s under investigation by the fire marshals. They will make a determination,” he said.

Fire marshals are routinely called in to investigate a fire if the cause has not immediately been determined.

Howe said he believed the fire actually started in his backyard and then spread to the house.

Howe, a lawyer, is well known in Bay Ridge business circles and in Brooklyn politics. He has served as president of the Merchants of Third Avenue, a business group representing store owners on the avenue, for more than 10 years. He is also a vice chairman of the Kings County Republican Party.

In the aftermath of the blaze, fire marshals were examining the house as Howe and his neighbor stood on the sidewalk and watched. Dozens of 81st Street residents were standing on their front porches looking on as the marshals conducted the probe. The air was filled with the smell of the fire.

Bob Howe and his family were welcomed by a neighbor who let them stay in his house, according to a friend of the family.The neighbor reportedly lives across the street from 168 81st St., the house in which the Howes had lived for 28 years.